Pneumatically driven plunger construction



Jan. 28, 1969 E. K. MOORE, JR 3,

'PNEUMAITICALLY DRIVEN PLUNGER CONSTRUCTION Filed June 19, 1967 Sheet of 2 ial 24 II s2 '50 48 a2 30 30 60 /4 x 92 3+ .J 89 a4 88 56 m 66 l as 43 40- 1 INVENTOR. Earl K Moore, J: BY 7 20 ,8 %arcusl. Ba 2525 PNEUMATI GALLY DR I YEN PLUNGER CONSTR U C T IDN Filed June 19, 1967' Sheet 2' of 2 50 g 74 V s6 W'll/ \F \d wig INVENTOR. 86 86 Ear/ K Moore, Jr.

, Q M07605 L, Bazes United States Patent 3,424,093 PNEUMATICALLY DRIVEN PLUNGER CONSTRUCTION Earl K. Moore, Jr., P.(). Box 2486, Odessa, Tex. 79760 I Filed June 19, 1967, Ser. No. 646,971 US. Cl. 10352 Int. Cl. F04b 17/00, 47/12 4 Claims ABSTRACT OF THE DISCLOSURE Background Pneumatically driven plungers for lifting well fluids in accordance with a cyclic action as determined by the frequency with which an outflow valve associated with the production tubing is opened and closed are disclosed by the prior art. These plungers sometime abut the upper and lower stop means with great force, and accordingly become inoperative because one or more of the complex multiplicity of parts necessary in the plunger construction of the pass art has exceeded its structural limitation. Malfunctions of this nature enable the plunger parts to either fail or become disassembled, thereby bringing about a costly fishing job. Furthermore, plungers of the past art sometime fail to open or to close upon striking the bumper pad or the lower stop means respectively, thus bringing about one or more improper cycles of the device and causing poor fluid recovery during this time.

Summary Therefore, a primary object of the present invention is the provision of a pneumatically driven plunger of the free piston type which'has a central packer section associated therewith which conforms to the inside peripheral wall surface of the production tubing in the fluid tight manner.

Another object of the present invention is the provision of a pneumatically driven plunger having a spring loaded packer section comprised of a multiplicity of outwardly depending parts which are adapted to conform to an irregular inside surface of a tubing.

Another object of the present invention is the provision of a free plunger having a 'valve associated therewith which permits the plunger to assume the flow permitting and flow preventing condition upon being decelerated in an upward or downward direction, respectively.

A still further object of the present invention is to provide a traveling plunger which is simple in design, rugged in construction, and which is economical in operation.

The above and other objects and advantages are attained in accordance with a plunger fabricated as set forth in the above abstract. The invention will best be understood, however, from the following detailed description when considered in conjunction with the drawings.

Brief description of the drawings FIGURE 1 is a side elevational view illustrating a preferred form of the device made in accordance with the present invention;

FIGURE 2 is a slightly enlarged perspective view of a portion of the device seen in FIGURE 1;

FIGURE 3 is a longitudinal cross-sectional view of the device seen in FIGURE 1, with some additional parts being illustrated, and with other parts being left in side elevation for clarity;

FIGURE 4 is a cross-sectional 'view taken along line 44 of FIGURE 3;

FIGURE 5 is a cross-sectional view taken along line 55 of FIGURE 3; and

FIGURE 6 is a fragmentary cross-sectional view, similar to FIGURE 3 except for the relationship of the various parts associated therewith.

Looking now to the details of FIGURE 1, taken in conjunction with the remaining figures, there is seen illustrated by the arrow at numeral 10 a pneumatically driven plunger, sometimes also called a free piston, having an upper body portion 12, a packer section 14, and a lower body portion 16. The lower portion 1 8 of a valve stem is seen depending from a horizontally disposed face 20 which forms a lower abutment means. The opposite end of the device terminates in a horizontally disposed face 22 which forms the upper abutment means of the plunger device.

The upper body portion is fabricated into an enlargernent 24 which reduces in diameter to form the neck 26 for the purpose of engaging a holding means when it is desired to stop the reciprocating travel of the plunger. Such a holding device is known in the art, and accordingly, will not be discussed in detail herein. A continuation of the valve stem portion 18 is received by the passageway seen at 27.

A packer section 14 is comprised of a matrix of parts which are fabricated in a manner that when assembled together, forms an expansible piston-like portion which engages the inside peripheral surface of a tubing wall, and as seen in the drawings, includes a multiplicity of packer segments 30 associated with a winged expander 32 or 34, all assembled together in the illustrated manner of the drawings. In particular, the embodiment disclosed in FIGURES 1 through 6 include three adjacent packer segments, each having three upper winged expanders 32 and three lower winged expanders 34 associated therewith. The details of the individual segments and expanders will be discussed more fully later on.

A series of lower and upper radial spaced passageways, 36 and 38 respectively, are seen laterally depending from the lower and upper body portions, respectively. The upper terminal end portion of the lower body portion terminates along the interface 40 of FIGURE 1, while the lowermost portion of the upper body portion terminates along the interface seen at numeral 42 of FIGURE 1. The upper interface 42 provides a downwardly depending skirt circumferentially described as the outer periphery of the upper body portion, as generally indicated by the numeral 42 in FIGURE 3. The lower interface at 40 provides an upwardly depending skirt circumferentially disposed as the outer marginal edge portion of the lower body portion as seen at 40 in FIGURE 3. Upper and lower skirt members, 42and 40 respectively, receive upper and lower depending lips 44 and 43 of segment 30. The lips, in conjunction with the skirts, enable each packer segment to be held movably captive, or caged, by the upper and lower body portions.

The upper end portion of the depending lip of each packer segment is provided with a cut-out 46 through which a stainless steel pin 47 is loosely received. The pin is rigidly peened to the upper body portion in the illustrated manner of FIGURE 3.

An upper portion of the packer segment is provided with an upper expander receiving slot 48 which is milled into the inside peripheral wall surface of the expander, and a cut-out 50 is provided in each sidewall of the segment, in the illustrated manner of FIGURE 2, for receiving part of the central body portion of the expander. Numerals 52 and 54 indicate a lower similar cut-out and slot, respectively. The relationship between the expander, the cutout, and the slot is best appreciated from observing the lowermost portion of FIGURE 2 in conjunction with FIGURE 1.

A multiplicity of spaced apart circumferentially extending grooves 56, 58, 60, and 62 are milled into the packer section for increasing turbulent flow to thereby offer increased friction to the flow of fluid between the plunger and the inside wall surface of a production tubing.

Upper and lower counterbores 64 and 66 provide a cage which receives a spring 65 therein with the spring being compressed between the mandrel and the segment.

The before mentioned valve stem extends diametrically through the plunger and includes a central portion 71 that forms an annular passageway 72 which communicates with the before mentioned lower and upper radially disposed passageways. The depending lower end of the mandrel threadedly engages the lower body portion in the manner illustrated at numeral 73. The lower depending end portion of mandrel 70 is chamfered to form a valve seat 74. Lower body portion immediately below radial passageways 36 is counterbored to provide a stop means 75. The valve stem includes a body element 78 which is enlarged and contoured to form a valve element 80 which can be moved into contact with the valve seat 74, and moved to the opposite position where the element contacts the before mentioned stop. The lower depending end of the valve stem is provided with lower and upper detents 82 and 83 respectively, which cooperate with a ratchet comprised of ball 84 and spring 85. Passageway 86 provides a loading hole which enables the spring and ball to be placed into the illustrated position of FIGURE 3 to thereby facilitate assembly.

Looking again to the details of the packer section, it will be noted that the expander is provided with oppositely curved arms 87 which outwardly depend from the main body portion thereof. The inside peripheral surface 88 of the expander is provided with a limited counterbore 89 which receives a spring therein in the same manner as previously discussed in conjunction with counterbores 64 and 66. The body portion of the expander is milled as illustrated at 90 to provide a surface which abuts against cut-out 50. Each edge portion 92 of a packer segment abuts against a similiar edge portion of an adjacent packer.

Operation In operation, the pneumatically driven plunger is free to reciprocate in a vertical direction within the production tubing of a well. With the packer in the position illustrated in FIGURES 1 and 3, the valve means associated therewith is in the open position, and accordingly fluid flow can occur through lower radial passageways 36, past val-ve element 80, through the annular fluid flow passageway 72, and out through the multiplicity of upper radial passageways 38. Accordingly, the packer is free to fall through the tubing since it is in the fluid flowing condition. Upon striking the stop means located at the bottom of the borehole, the lower valve stem portion 18 is driven upwardly into the position generally illustrated in FIGURE 6, whereupon the valve element 80 seats against the valve seat 74 to thereby close the fluid flow annulus 72, to thereby prevent the flow of fluid therethrough. In assuming the configuration of FIGURE 6, the ratchet ball at 84 releases detent 83 and locks the valve stem into the illustrated position by engaging detent 82, to thereby hold the valve in the illustrated position of FIGURE 6. The plunger is now in the flow preventing position, since fluid cannot flow past the closed valve element 80. Accordingly, when the outflow valve of the well is opened, differential in pressure across the packer causes the plunger to travel upwardly through the tubing, thereby carrying 4 with it a load or slug of fluid. When the packer reache the stop means or bumper pad associated with the lubricator, the upper terminal end 76 of the valve stem will be returned to the position of FIGURE 3, which is the flow permitting position, and accordingly, the plunger is free to drop back to the bottom of the tubing.

The packer section 14 provides an effective seal as it lifts the fluid within the well tubing, since the expansible segments, along with the expanders, remain resiliently urged in an outwardly extending direction against the wall of the tubing, yet are able to conform to the irregularities of the tubing. In order for flow to occur across the plunger, fluid must flow across the multiplicity of annular grooves as seen at 56. Since the outer surface of the individual segments and expanders are spring-loaded against the tubing wall, very little flow thereacross is possible. Fluid flow that occurs between interface 92 of adjacent segments is intercepted by the upper and lower expanders. Accordingly, the packer section is a matrix of assembled parts, all of which are outwardly biased against the inside wall of a tubing to thereby form an expansible packer section which precludes significant fluid flow thereacross.

The device illustrated by the above embodiment is assembled by first inserting ball 84 and spring through passageway 86 into the illustrated position of FIGURE 3. The valve stem is then inserted into the lower body portion. Packer segments 30 are provided with springs 65 at each indicated position, one at a time, and compressed against the central mandrel 70 by merely pressing the segment against the mandrel and sliding it in an upward direction to permit the upper depending lip 44 to slide under the downwardly depending skirt 42 with cut-out 46 receiving its proper pin. The expanders 32 must each be in their proper location prior to assembly of the last segment. The lower body portion containing the valve assembly is then telescoped into the position of FIGURE 3, and the threads 73 made up. The device is now assembled and ready to be dropped into the well.

For purposes of illustration, a single embodiment having only three segments and three sets of expanders has been shown. It will occur to others skilled in the art to effect certain modifications on the instant invention, including changing the arrangement of, as well as the number of, packersegments and expanders. Therefore, the metes and bounds of the present invention should not be limited to the above descriptive portion of this disclosure, but rather should be interpreted in light of the following claims.

I claim:

1. In a pneumatically driven plunger for reciprocating within the tubing of a well, a mandrel having an upper abutment face, a packer section, and a lower abutment face;

means forming a flow passageway through said mandrel for providing fluid flow within said packer section;

valve means associated with said passageway and adapted to assume an opened position upon said upper abutment face being rapidly decelerated, and to assume a closed position upon said lower abutment face being rapidly decelerated;

said packer section is comprised of a multiplicity of circumferentially disposed packer segments, each having rneans forming upper and lower depending lips; said upper body portion of said mandrel including a circumferentially disposed downwardly depending skirt; said lower body portion including an upwardly depending circumferentially disposed skirt; said upper and lower lip, respectively, being received within said upper and lower skirt, respectively, to thereby loosely hold said packer segments caged therein;

each said segment further includes vertically extending edge portions, means forming cut-outs in adjacent edge portions of said segment, and means forming a slot extending between said cut-outs on the inside surface of the segment;

an expander having a body portion with curved arms radiating therefrom, said body portion being received within the cut-out of adjacent segments and with said radiating arms extending into said slot of each adjacent segment.

2. The plunger of claim 1, and further including means forming a cut-out in the marginal edge portion of a lip of one said segment;

means forming an aperture through said downwardly disposed skirt;

a radially extending pin received through said cut-out and aperture for maintaining the segments aligned with said mandrel.

3. The plunger of claim 1, wherein said valve means includes an elongated valve stem arranged coextensively with said passageway and including a valve element attached thereto wherein said valve element forms part of said valve means; and

a valve seat associated with said mandrel and adapted to cooperate with said valve element to thereby permit fluid flow when said valve element is unseated therefrom and to prevent fluid flow when said element is seated therewith.

4. The improvement of claim 1 wherein said valve stem is longer in length than the distance between said faces of said plunger, with said valve stem being arranged for longitudinal reciprocation with respect to said plunger; the lowermost portion of said valve stem depending from said lower abutment face when said valve is open, and the upper terminal end of said valve stem extending from said upper a butment face when said valve is closed; whereby: impact of said plunger against the bottom stop means moves said valve stem to its closed position and impact of said plunger against an upper stop means moves said valve to the opened position to thereby enable the plunger to assume the fluid flow preventing condition as it strikes the lower abutment means and to assume the fluid flow permitting position as it strikes the upper abutment means.

References Cited UNITED STATES PATENTS 2,821,142 1/1958 Knox 103-52 3,055,306 9/1962 Tausch 103-52 3,090,315 5/1963 Milton 103-52 3,176,619 4/ 1965 Shaw 10352 ROBERT M. WALKER, Primary Examiner. 

